<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

</head>
<style>
    .container {
        overflow: hidden;
    }

    .left {
        width: 300px;
        background-color: yellow;
        height: 300px;
        float: left;
    }

    .right {
        background-color: blue;
        height: 300px;
        margin-left: 300px;
    }
</style>

<body>
    <!-- 
        两种方式实现：
        1、左列定宽，右列自适应
            1）浮动+margin
        2、左列不定宽，右列自适应
     -->

    <div class="container">
        <div class="left"></div>
        <div class="right"></div>
    </div>
    <script>
        var arr = [1,2,3];
        var b = arr.concat([4,5]);
        arr.find((v) => v > 1)
        console.log(arr.join(''));
        console.log(arr.findIndex((v)=> v > 1));
        console.log(arr);
        console.log(b);
    </script>

</body>

</html>